Such a valve device is known from the document DE 10 2010 005 229 A1. In the known solution, any disruptive influence on the valve piston caused by friction forces or flow forces can be compensated for without control effort or regulating effort by increased discharge of pressurizing medium from the respective pilot control compartment. As a result, the main piston is further displaced towards the desired position.
If the electric current for one of the two electromagnets is reduced or switched off, the pilot control piston is preferably additionally moved by an energy storage device, commonly in the form of a compression spring, towards a position that blocks the fluid-conducting connection between the activated pilot control compartment and the assignable tank connection. The pressure that builds up again in the pilot control compartment then pushes the main piston back towards its rest position.
In the same manner as described above, the main piston can be axially displaced in the opposite direction when the additional second electromagnet is energized. In this way, the second consumer connection can be connected to the pressure connection and the first consumer connection can be connected to the tank connection. Although the known solution provides a valve device that permits functionally-reliable operation, even in the case of difficult operating conditions, the known solution is not entirely satisfactory with regards to improving performance and simultaneously reducing the valve design size.